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Four year experiments were conducted to find out the causes of yield reduction of farmer’s field of Nepal from 2011 to 2014. Randomised complete block design with three replications were used to compare twelve rice genotypes with Khumal-4 as a standard check. One set of genotypes were transplanted in the last week of June and the other set was transplanted two weeks delayed as summer season rice. Results showed that rice different parameters like grain yield, plant height, panicle length, days to heading and days to maturity were found significant (p<0.05). Plant height, panicle length and fertile grain per plant were also found significant in early transplanted rice than delayed transplanted rice. Delayed transplanted aged rice seedlings took shorter days to flower and mature than early transplanted rice. On an average, 38.44% decrease in yield was found from early to delayed transplanted rice from 2011 to 2014. Similarly, grain yield of early transplanted rice was found higher than delayed transplanted rice in all the year. The reason could be that too early and too late transplanting could not fulfill the required temperature and photoperiod for rice crop. Late transplant of aged rice seedlings are severe to cold and effect plant growth and yield. Thus the yield reduction of farmer’s field can be minimised by transplanting rice in appropriate time with recommended package of practices.